Apparatus for burning pulverized fuel.



I. B. CRAM.

APPARATUS FOR BURNING PULVERIZED FUEL.

APPL ICAT|ON FILED JULY 9. 1915.

- Patented Mar. 12, 1918.

UNITED, STATES PATENT OFFICE.

TIM B. CRAM, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE RAILWAY MATERIALS COM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

APPARATUS FOR BURNING PULVERIZED FUEL.

Specification of Letters Iatent. Patentcu y ar, 12,1918.

Application filed July 19, 1915. Serial No. 40,636.

- Illinois, ha'\ e invented certain new and useful IlllPl'OVQlllBfltS 1n Apparatus for Burn-- I ing Pulverized Fuel, of l. -,-in%is n specification.

his invention relates 'to-an apparatus for urning carbonaceous fuel andfwhile pur which the followge rbonaceous fuel. L "1 H L h s im-a n en ,7 qppgfifimf Jflfhich is ip r icy m lgi neoessity" .Ofdepending on v, an;-

i "itiontemperutui'e, the 'hesit beingdef rivedffrom-the'combustionof a portion of 3 theffuel itself." 5

f, Another object of my invention is-the pi'o-' i'zisio'n of'ain apparatus for burning pulveriz" solid fuel in which the fuel may be ignited directly by means of e torchfwithout 8B the" necessity of preheating theburner as has b "necesssryavith furnacesof types here- "fore' known. i e

---'Aisti'll'further object of my. invention is ,the provision of an app'aratusvfor burning mfpujlverized solid .fuel whichvis so constructed Wit-hat combustion is almost-instantaneous and companying drawing, in which through the burner;

o 'ilarlyflndapted to the burning of pulverjajd .so lid fuel,' it js applicable, with good sults'toftheiburninaof' othe' "formsof name-- 7 heating. poi'er without identalwtQ' 1on from 'th'e iwslls'of the furn gcefto supplythe vhent'necessaq' to bring-the fuel to the Still another object of my invention is the stood by reference to the following specificatron when read in connection with the ac- Figure 1 is rm elevation partially in sectron of a furnace equipped "with .a, burner according to my inyentiOm-tOgethefiflith a controller for supplying fuel and Fig. 2 is an enlarged yertieal section bib Heretofore two methods fli enr c ple dfrr ujmg'" .hiPiVith thef 'fii el'" g i. fused state in'tbthe'iljtinefihflin This $0 produces n 'luzy srhoky name, offlo exiting vvalue, which is totally abridged-fer rnost purposesand hence .hus' meteivithjno success in the practiculart.

With the constantly. risingfprice iof fuel oil 'it is extremifly desirable th it":ap'pa,ret-us' be devised, whereby 'p\'1l i eri z'e;d sohd fuel, Su h, as i h teeb i ustwe etcl; may be burned'with ifjcle'a rfsh'ortf arms suchas is alrendy possible"tQIatteinisVith oilburners. I

Referring mule gmw ii sfiideighms a. small forging .furn'ace flndi ijsind olitive merely of a large clssis of furnaces towhich my invention is applicable and2 designstes 96 generally the burner according to'myimvention, which is attached to oneside" ofthe furnace and is connected'by nieans of a pipe 3 to a source of; pulverized fuel, in'this instance a. controller 4. The pulverized fuel is drawn into the pipmB b means of an mjector 5, supplied with air under pressure from a, pipe 6 and controlled by a 'valve 7. Air is supplied to the burner through a pipe and'lB, in this instance disposed normal to 8, connected to any suitable source of supply under pressure, and is .controlled by a valve 9 in the pipe.

The burner comprises the walls 10, con

structed of refractory material, such as fire brick, and is supported in any suitable manneradjacent one side of the furnace 1, a metal bracket 11 being provided in this instance to support the burner. The burner is provided with two distinct chambers 12 each other, which may be termed,- respec- .tively, the preheating and final combustion chambers, and a passage 14 of smaller crosssectional area than the chamber 12, communicating with one end thereof and arranged substantially concentrically therewith. At the junction of the chamber 12 and the passage 14, the, shoulder 15 is formed, the function of which will presently appear. It is to be understood that the chambers-12 and 13 and the passage 1% may be circular in section or of any other suitable form.

A nozzle 16 enters the end of the passage '14 remote from the shoulder 15 and is adapt-.

ed 'to be connected to the pipe 3 to direct a unction of the duct'18 and the pipe 8, and

adapted to control the air supply. A duct 19 leads from the duct 18 to a-point adjacent the junction of the chambers 12 and 13 and is adapted to supply the final combustion air and to direct the resulting combus- I tion products in the desired direction. The

as an injector to draw the fuel from jet of air issuing from the duct 19 also acts chamber 12. In the form of the burner disclosed in the accompanying drawing the jet of final combustion air from the duct- 19 has a direction normal to thedircction of the fuel jet, but it is to he understood that this is merely illustrative and that it may be directed as desired. A lighting hole 20 is provided in the wall of the passage 14 adjacent the end of the nozzle and a suitable plug 21 is normally disposed therein.

The method of operation is as follows: The pulverized solid fuel is drawn from the controller 4: into the pipe 3 by means of the injector 5 and is forced in the. form of a fuel cloud, with the solid particles suspended in a limited quantity of air, into the nozzle 16 and thence into the passage 14 and the chamber 1'2 in the form of a jet. The valve 7 may be set to deliver the desired quantity of fuel at the returned velocity to the nozzle. It may mien that the best results are ohthe tained when the fuel is finely pulverized so that. approximately 95% would pass through a 200-mesh screen and when it is delivered at a velocity of approximately 4500 feet per minute. This insures the proper 'sus enslon of the fuel in the air and prevents c ogging of the pipes and the nozzle. The valve 9 is then operated tbadmit air through the ducts 18 and 19 to the burner and a torch is applied outside the lighting hole 20 and the flame is drawn into the chamber 12 to ignite the fuel in the preheating combustion chamber. Ignition will take place instantane. ously, exactly as in the ease of gas or oil, it being unnecessary to preheat the burner, according to the usual practice with pulverized solid fuel burners. Ignition will take place only within theehamber 12 since flame propagation rearwardly of the shoulder 15 isprevented thereby, and the passage 14 and the metallic members 16 and 17 remain cool through the entire operation of the furnace.

The velocity in excess of t by reason of the 'air of the jacket surroundin of the air should be slightly e velocity of the fu'el jet and difference in velocities the the fuel jet draws particles off-.101 away rom the edges thereof and the arrangement of. the chamber 12 is such that these particles whirl away 'fromthe jetyas indicated in Fig. 2 of the drawing,

owing to the tendency'of the fuel and air jets to reduce the pressure near the walls of the chamber. This causes the articles of fuel to become thoroughly mixe with the air to form a combustible m xture, which burns when ignited and preheats the remainder of the fuel in the jet as it passes ownwardly to the final combustion chamber 3.- Thefuel" of the jet during its travel to the final combustion chamber 13 is preheated to the i ition point and at the lower end ,o'f the'c amber 12 it meets the 'et of air from the duct 19, which is su cient in quantit to complete the combustion of the fuel. glombustion is almost instantaneous, being pract cally complete at the entrance of the furnace'and the incandescent combustion products pass into the furnace in the form of a clear, short and very hot flame.

It will be seen from the foregoin that l have devised a novel apparatus for liurning carbonaceous fuel, whereby a short flame free from smoke may be produced. The apparatus possesses an advantage in addition to its adaptability to the'method described in that the metal parts may be kept cool without waterjacketmg or other artificial cooling means and the life of the parts is correspondingly longer and the burner is less expensive to maintain.

It will be obvious that various changes may be made in the form, construction and arrangement of the parts without departing from inc spirit and scope of the invention or recruitin any of its material advan- (ages, the form llll'tiHlJt'fUXC described being merely a preferred embodiment thereof.

I claim:

1. In a fuel burner, the combination of Walls of refractory material forming an elongated combustion. chamber and a concentrically arrangetLj); ssage of smaller cross-sectional area lea n thereto, said alls providing an abrupt ,iinperforatc Bhoulder at the 'uncture of saiil'cluimber and passage, a nozzle at the end of said PtL SSUgL, remote from said shoulder for injcctlngjfuel into said passage and chamber fornnn'g' in fuel jet, amLan inlet concentric with said nozzle and ending in the plane of the end thereof to supply a surrounding jacket of air to support a limited combustion of Said fuel, said shoulder being adapted to prevent [lame propagation rearwardly thereof and to assist in causing eddy currents about said fuel jet whereby a portion of the fuel is Withdrawn from the jet and mixed with the surrounding air.

2. In a fuel burner, the combination of walls of refractory material forming an elon lzated combustion chamber and a concentricall) arranged passage of smaller crossscc tional area than said chamber leading thereto, said walls providing an abrupt imperforuto shoulder at the juncture of said chamber and passage, a nozzle at the end of said passage emote from said shoulder for injecting fuel into said passe e and chamber forming a fuel jet, an in ct concentric with said nozzle and ending in the plane of the end thereof to supply a surrounding jacket of air to support a limited combustion of said fuel within said chamber, said shoulder being adapted to prevent flame propagation rea rwardly thereof and to assist in causing eddy currents about said fuel jet \\'l1ereby a portion of the fuel is Withdrawn from the jet and mixed with the surrounding air a second chamber formed by said walls ad acent the end of said first-mentioned chamber and at a right angle thereto, and an inlet at the juncture of said chambers to direct a supply of air into said second chamber in the direction of its axis.

TIM B. CRAM.

Witnesses:

J. G. CONTANT, Gus Bwmm. 

